Chargers running back Ryan Mathews practiced in a limited role Friday, his first on-field activity of any kind this week after sitting out with a neck injury.

The third-year pro hasn't played when he didn't practice during the week, so his participation in individual and team drills offers a glimmer of hope that he could be active Sunday against Denver.

Mathews was listed as questionable on the team's official injury report, which was released after Friday's practice.

Chargers left tackle Jared Gaither missed his fifth straight practice in deference to a groin injury. He was listed as doubtful, and it's highly unlikely that he will play at Denver. Rookie Mike Harris is expected to make his sixth start in Gaither's stead.

Nose tackle Aubrayo Franklin was declared out with a knee injury. He won't play Sunday. Antonio Garay will start in his place.

Injury news was better for a number of players who missed portions of practice this week. Outside linebacker Antwan Barnes (hamstring) was a full participant and is probable to return after missing last week's game at Tampa Bay

Right guard Tyronne Green (ribs/illness), safety Eric Weddle (knee/illness) were designated as probable. Safety Atari Bigby (quad) was limited this week in practice, but is probable and will play.

Tight end Dante Rosario (hamstring) was limited in practice and is questionable.